Abiotic stresses such as salt, drought and low temperature are the most limiting and least controllable factors in crop production. From a world perspective these stresses have the most significant impact on yield. As more land becomes salinized through poor water quality, salinity impacts on crop production is becoming increasingly important worldwide (Winicov, 1998). Continued use of fresh water has significantly and, in some cases, alarmingly lowered the water table in many cropland areas, forcing low-water regimes on growing plants and leading to poor performance. Among many affected areas around the world, prairie lands by nature, appear to be very prone to such phenomenon. Recent drought in Saskatchewan, a land that produces the best quality wheat and canola, has severely affected the crop yield. Finally, low temperature impact on plant performance and low yield world wide and, in particular, in the prairie provinces is a persistent problem.
There exists a continuing need to develop plants and crops that exhibit improved resistance to plant stresses, thereby increasing crop yields in adverse conditions and reducing the risk of crop failure. For example, plants with increased tolerance to drought, extreme temperatures and higher salt conditions may open the possibility of farming in semi-desert climates, where agriculture was previously non-viable. In addition, the development of novel crops with improved tolerance to cold or freezing temperatures may significantly prolong the growing season in regions with colder climates.
A number of plant genes are known to show increased levels of expression when plants are exposed to stress. However, despite considerable efforts to engineer genetically modified crops with increased stress tolerance, to date there are little or no such crops on the commercial market.
The future prospects of engineering novel plants with an increased capacity to tolerate environmental insults will depend on the modulation of critical stress tolerance controlling genes, and knowledge of their functional regulatory properties. The inventors for the present application, and others, have endeavored to decipher the mechanisms of plant stress tolerance in the hope of developing an understanding of the biochemical pathways involved. Nonetheless, the characterization of the genes and proteins involved in plant stress responses presents a number of significant challenges.
There remains a continuing need to develop a better understanding of plant stress responses, so that corresponding methods can be developed to confer advantageous properties to plants. This need extends to the production of crops that exhibit resistance to damage by adverse climatic conditions such as excessive temperatures, drought, and conditions of high salinity. Even incremental gains in plant stress tolerance may have a significant economic impact in stabilizing the quality and supply of grain, oilseed and horticulture. Enhancement of germination, growth and flowering are extremely important in regions that have a short or otherwise difficult growing season.